Tests of impulse fans confirm performance in car-park fires
Tests of impulse fans to control the flow of smoke in enclosed car parks during fire have confirmed the predictions of computational fluid dynamics (CFD) used by Colt for system design. The series of test was carried out by BRE and Colt in a simulated car park. The tests were carried out to demonstrate how an impulse ventilation system can be used to control smoke in a car park and keep large areas effectively free of smoke — enabling firemen to see and approach close to the fire in good conditions. Such systems can be offered as an alternative to a sprinkler system. A further object of the tests was to prove the effectiveness of CFD in predicting the spread of smoke in a car park with impulse fans. The test rig of 35 x 30 x 3 m was set up in a simulated car park at a test facility in Middlesbrough. The two ends of the rig were open but protected from the effects of wind. Ventilation was provided by two Colt Cyclone 100 fans at 80% of full speed (65% thrust). These were sited to restrict the smoke to one side of the test rig and keep the other side substantially free of smoke. A car shell containing a tray of diesel was ignited to create a 1 MW fire. Paul Compton, smoke-control executive at Colt International, explains, ‘Impulse fans have been shown to provide a system capable of limiting smoke flows to a predefined area, allowing their use to assist fire fighting or to protect means of escape. The similarity of the test and CFD results means that approving authorities can now confidently accept validated CFD analysis as proof of performance for an impulse system without the need for hot smoke tests on the completed system.